Alteration of Bile Acid and Cholesterol Biosynthesis and Transport by Perfluorononanoic Acid (PFNA) in Mice

Toxicol Sci. 2018 Mar 1;162(1):225-233. doi: 10.1093/toxsci/kfx237.

Abstract

Perfluorochemicals produce hepatotoxic effects via activation of peroxisome proliferator-activated receptor alpha (PPARα) and constitutive androstane receptor (CAR) nuclear receptors in animals. Bile formation is one major liver function. But it remains unknown whether perfluorochemicals alter metabolism of bile acids (BAs) in liver. The present study was designed to determine the impact of perfluorononanoic acid (PFNA) on BA and cholesterol homeostasis in mice. A single dose of PFNA (0.1 mmol/kg) was intraperitoneally administered to adult male wild-type (WT), PPARα-null, and CAR-null mice. PFNA caused cholestasis in the WT mice, indicated by increased serum alanine aminotransferase, hyperbilirubinemia, elevated BA concentrations in mouse serum, and appearance of bile plugs in mouse liver. In addition, PFNA decreased total and some individual BAs in mouse liver. PFNA increased the concentrations of total and taurine-conjugated, as well as some individual BAs in the serum of WT and CAR-null mice but not in PPARα-null mice, indicating a PPARα-dependent mechanism. PFNA decreased mRNA expression of most BA-related transporters (sodium-taurocholate cotransporting polypeptide, organic anion transporting polypeptide [Oatp]1a1, Oatp1b2, and bile salt export pump) and BA biosynthetic enzymes (Cyp7a1, 7b1, 8b1, and 27a1) in mouse liver, but increased mRNA expression of some efflux transporters (breast cancer resistance protein, multidrug resistance transporter 2, multidrug resistance-associated protein [Mrp] 2, Mrp3, and Mrp4), primarily via a PPARα-dependent mechanism. Moreover, PFNA increased free and total cholesterol in mouse liver but not in mouse serum. Furthermore, PFNA increased mRNA expression of sterol transporters, namely Abca1, g1, g5/g8, and steroidogenic acute regulatory protein via PPARα. In conclusion, PFNA produced cholestasis in mouse liver, and the activation of PPARα plays a central role in regulating BA and cholesterol metabolism and transport in mouse serum and liver.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Bile Acids and Salts / biosynthesis*
  • Bile Acids and Salts / blood
  • Biological Transport / drug effects
  • Cholestasis / chemically induced*
  • Cholestasis / metabolism
  • Cholestasis / pathology
  • Cholesterol / biosynthesis*
  • Cholesterol / blood
  • Constitutive Androstane Receptor
  • Environmental Pollutants / toxicity*
  • Fatty Acids
  • Fluorocarbons / toxicity*
  • Liver / drug effects*
  • Liver / metabolism
  • Liver / pathology
  • Liver Function Tests
  • Male
  • Mice, Inbred C57BL
  • Mice, Knockout
  • PPAR alpha / genetics
  • PPAR alpha / metabolism
  • Receptors, Cytoplasmic and Nuclear / genetics
  • Receptors, Cytoplasmic and Nuclear / metabolism

Substances

  • Bile Acids and Salts
  • Constitutive Androstane Receptor
  • Environmental Pollutants
  • Fatty Acids
  • Fluorocarbons
  • PPAR alpha
  • Receptors, Cytoplasmic and Nuclear
  • perfluoro-n-nonanoic acid
  • Cholesterol